accept-charset

A list of character encodings that the server accepts. The list can be delimited by spaces or commas. The browser uses in the order in which they are listed. The default value is the reserved string "UNKNOWN", in which case the encoding corresponds to the encoding of the document containing the form element.
HTML 4: In previous versions of HTML, the different character encodings could be delimited by spaces or commas. This is no longer the case in HTML5, where only spaces are correct.

autocomplete - HTML5 (HTML5 전용)

Indicates whether controls in this form can by default have their values automatically completed by the browser. This setting can be overridden by an autocomplete attribute on an element belonging to the form. Possible values are: • off: The user must explicitly enter a value into each field for every use, or the document provides its own auto-completion method; the browser does not automatically complete entries.
• on: The browser can automatically complete values based on values that the user has entered during previous uses of the form.

enctype

When the value of the method attribute is post, this attribute is the MIME type of content that is used to submit the form to the server. Possible values are:
•application/x-www-form-urlencoded: The default value if the attribute is not specified.
•multipart/form-data: Use this value if you are using an <input> element with the type attribute set to "file".
•text/plain (HTML5)
This value can be overridden by a formenctype attribute on a <button> or <input> element.

method

The HTTP method that the browser uses to submit the form. Possible values are:
•post: Corresponds to the HTTP POST method ; the data from the form is included in the body of the form and is sent to the server.
•get: Corresponds to the HTTP GET method; the data from the form are appended to the action attribute URI, with a '?' as a separator, and the resulting URI is sent to the server. Use this method when the form has no side-effects and contains only ASCII characters.
This value can be overridden by a formmethod attribute on a <button> or <input> element.

novalidate - HTML5 (HTML5전용)

This Boolean attribute indicates that the form is not to be validated when it is submitted. If this attribute is missing (and therefore the form is validated), this default setting can be overridden by a formnovalidate attribute on a <button> or <input> element belonging to the form.

target

A name or keyword indicating where to display the response that is received after submitting the form. In HTML 4, this is the name of, or a keyword for, a frame. In HTML5, it is a name of, or keyword for, a browsing context (for example, tab, window, or inline frame). The following keywords have special meanings:
•_self: Load the response into the same HTML 4 frame (or HTML5 browsing context) as the current one. This value is the default if the attribute is not specified.
•_blank: Load the response into a new unnamed HTML 4 window or HTML5 browsing context.
•_parent: Load the response into the HTML 4 frameset parent of the current frame or HTML5 parent browsing context of the current one. If there is no parent, this option behaves the same way as _self.
•_top: HTML 4: Load the response into the full, original window, canceling all other frames. HTML5: Load the response into the top-level browsing context (that is, the browsing context that is an ancestor of the current one, and has no parent). If there is no parent, this option behaves the same way as _self.
HTML5: This value can be overridden by a formtarget attribute on a <button> or <input> element.